1. Technical Field
The present invention belongs to the field of robotics, and particularly relates to a servo.
2. Description of Related Art
Servos are initially used in vessels for realizing their turning functions. Since their rotation angles can be continuously controlled by programs and servos further have advantages of small volume, light weight, large torque, and large accuracy, they are thus widely used in smart vehicles for realizing turnings and in various motions of joints of robots. What needs to be noted is that robots have many joints, and each joint is called by us to be one degree of freedom. Average machine bodies have a dozen degrees of freedom. In this way, it can ensure the flexibility of motions. In the machine bodies of robots, we usually use servos as connection parts of each joint, and servos can accomplish positioning and motions of each joint.
Conventional servos of robots usually use potentiometers to defect rotation angle of servos. Servos mainly include a servo disc, a speed reduction gear set, a potentiometer, a DC motor and a circuit board. The circuit board receives control signals from signal lines and controls the motor to rotate. The motor drives a series of gear sets, and motions are transmitted to the servo disc after speed reduction. An output shaft of the servo disc is connected to the potentiometer. The servo disc drives the potentiometer as it rotates. The potentiometer detects the rotation angle of the servo and outputs a voltage signal to the circuit board for feedbacking. The circuit board then determines the rotation direction and rotation speed of the motor according to a position where the output shaft rotates, thereby stopping a target. However, the conventional method of using potentiometers to detect rotation angle of servos, has restricted detection accuracy because potentiometers are realized by adjusting the value of voltage (including direct current voltage and signal voltage) and current, and voltage tends to be disturbed by surrounding environment (e.g., temperature, sealing, etc.) and fluctuates. Meanwhile, potentiometers make servos heavy in weight.
In summary, there mainly exists the following problems in the servos of prior arts: Firstly, potentiometers tend to generate errors due to being affected by environment during detecting the rotation angle of servos, thereby resulting in that potentiometers are unable to accurately detect the rotation angle of the servos. Secondly, the servos are heavy in weight because of using potentiometers.